Indiana UST Closure Requirements - Assessment, Sampling, and Reporting
Indiana UST closure under 329 IAC 9-6. Procedures, advance notification, soil and groundwater sampling requirements, site assessment reporting, and closure.
Overview
When an underground storage tank (UST) system in Indiana is permanently closed, closed in place, or undergoes a change in service, the owner or operator must perform a site assessment under 329 IAC 9-6. The assessment determines whether petroleum has been released from the UST system and whether contamination exceeds screening levels.
Indiana’s UST closure process is administered by IDEM’s Petroleum Branch within the Office of Land Quality. The closure contractor performing the physical work must be certified by the Office of the State Fire Marshal.
This guide covers the closure notification, site assessment sampling, reporting, and what happens when contamination is discovered. It does not cover temporary closure (which was repealed from 329 IAC 9-6-5) or the ongoing corrective action process that follows if a release is confirmed.
Types of UST Closure
Indiana recognizes three types of UST system closures under 329 IAC 9-6:
Removal. All USTs, piping, and dispensers are physically removed from the ground. This is the most common closure type and allows the most thorough site assessment because the excavation exposes native soil for direct sampling.
In-place closure. Some or all of the USTs, piping, and dispensers are closed without removal. In-place closures require prior IDEM approval. Conditions that may qualify include situations where all or a portion of the system is inaccessible due to buildings or structures. The tank must be emptied, cleaned, and filled with an inert solid material.
Change-in-service. The UST system is converted from storing regulated substances to unregulated substances. Change-in-service closures also require prior IDEM approval.
Advance Notification
The UST owner or operator must notify IDEM’s Closure Coordinator at least 14 days before scheduled closure activities begin. IDEM Petroleum Branch staff may be present on-site to inspect the closure.
Failure to provide advance notice, or to notify IDEM of schedule changes, is a violation of 329 IAC 9-3-1(a) and may be referred to enforcement.
Contact the UST Branch at (317) 233-5745 for scheduling. The Closure Coordinator as of the most recent IDEM correspondence is Nawal Hopkins, Senior Environmental Manager.
Closure Contractor Certification
The person on-site during closure who performs the physical UST closure work must be certified by the Office of the State Fire Marshal. The contractor’s name and certification number must be included in the site assessment report.
Site Assessment Sampling Requirements
Sampling requirements are specified in 329 IAC 9-6-2.6 and vary by closure type.
Removal Closure Sampling
For removal closures, native soil samples must be taken from the following areas:
UST excavation. Each UST excavation must be sampled separately. Composite samples are not acceptable. All samples must be discrete grab samples taken directly from undisturbed native soil at the base and sidewalls of the excavation. Sidewall samples must be taken at a point half the distance from the surface to the bottom of the excavation.
Piping and dispenser islands. Native soil under piping and dispenser islands that routinely contained regulated substances must be sampled with discrete grab samples. Piping must be sampled every 20 feet (or fraction thereof) along the piping run. If the piping run is less than 20 feet, one sample is taken at the midpoint between the UST excavation and the pump or dispenser island.
Exception for piping directly above USTs. Soil sampling under piping and dispenser islands is not required if all dispensers and piping that routinely contain product are located directly above the UST system being closed and the location is documented.
Remote fill lines. If a remote fill line is 20 feet or more, soil samples must be taken every 20 feet. If less than 20 feet, one sample at the midpoint.
Excavated soil and backfill. Native soil and backfill to be returned to the UST excavation must be sampled at a rate of one discrete grab sample per 50 cubic yards, using the exposure criteria in IC 13-12-3-2.
In-Place Closure Sampling
For in-place closures, soil borings must extend at least 2 feet below the elevation of the base of the UST.
If the boring depth is 15 feet or less, a minimum of two soil samples are required at the point where a contaminant is detected - one from the upper portion and one from the lower portion of the boring.
If the boring depth is greater than 15 feet, a minimum of three soil samples are required: the shallowest sample must be taken at least 1 foot below grade, and additional samples must be taken where the release is suspected or detected.
In-place closure sampling requirements may not be waived.
Groundwater Sampling
A groundwater sample must be collected within any area where a suspected contaminant release has occurred or where a chemical of concern has been confirmed through visual staining, field screening, petroleum odors, or laboratory analytical results. Groundwater sampling requirements must be completed in accordance with 329 IAC 9-6-2.6(d).
Chemicals of Concern
The chemicals of concern for sampling depend on the product stored in the UST. The R2 (Risk-based Closure Guide, WASTE-0046-R2) Table 2-A lists chemicals of concern for various product and waste types by media. For product types not included in Table 2-A, contact the IDEM Closure Coordinator.
For USTs containing hazardous substances (not petroleum), the owner and operator must perform sampling and analysis for the specific chemical of concern (329 IAC 9-6-2.5(g)).
Sampling Waiver
A waiver of UST system closure sampling requirements may be requested in writing under 329 IAC 9-6-2.6(e). The written request must be submitted to the Closure Coordinator, who will issue a determination after review.
Site Assessment Report
The site assessment must be submitted to IDEM within 30 days after completion of permanent closure or change-in-service (329 IAC 9-6-2.5(a)).
The report must be submitted using the UST Systems Closure Report (State Form 56554) and must include:
Owner/operator information, including all owners or operators during the last 25 years. UST system details (size, product stored, installation date, closure type). Closure contractor information and State Fire Marshal certification number. Site proximity to sensitive areas (residences, schools, wells, well fields, wellhead protection areas). Site-specific maps showing drainage features, above and below-ground features, sample locations, and surrounding land uses. Laboratory analytical results for soil and groundwater samples in tabular format, with signed laboratory certificates of analysis.
Spills Discovered During Closure
Spills and Overfills (329 IAC 9-4-4)
If a spill or overfill of petroleum is discovered during closure activities that equals or exceeds 25 gallons and results in a release to the environment, the owner/operator must contain and immediately clean up the spill and report it to the IDEM emergency response 24-hour spill hotline at (888) 233-7745 (in-state) or (317) 233-7745 as soon as possible but within 24 hours.
Spills or overfills of less than 25 gallons that do not reach a surface water body and are cleaned up within 24 hours must still be contained and cleaned up but do not require reporting (329 IAC 9-4-4(b)).
Contamination Exceeding Screening Levels
If closure sampling reveals contamination above IDEM’s Published Levels (screening levels), the site assessment enters IDEM’s petroleum remediation program. The RCG (WASTE-0046-R2) applies, and the site will need further investigation to characterize the release and determine whether remediation is needed.
ELTF reimbursement may be available for eligible sites. The 60-day Initial Site Characterization deadline for ELTF coverage begins when the release is reported - do not delay.
Closure Report Complete
Once all requirements of 329 IAC 9-6 are satisfied and sampling shows no contamination above screening levels, IDEM issues a Closure Report Complete determination. This confirms the UST closure is complete. If contamination was found, the site is tracked separately through the LUST program until NFA status is achieved.
Comparison to Ohio BUSTR Closure
| Indiana | Ohio | |
|---|---|---|
| Governing rule | 329 IAC 9-6 | OAC 1301:7-9-13 |
| Advance notice | 14 days to IDEM Closure Coordinator | Permit from BUSTR or delegated fire department |
| Closure contractor certification | State Fire Marshal certification required | BUSTR-licensed contractor required |
| Report due | Within 30 days of closure completion | Within 90 days of closure completion |
| Soil sampling (removal) | Discrete grabs from base, sidewalls, piping every 20 ft | Per BUSTR TGM - base, sidewalls, piping |
| Groundwater required? | If contamination suspected or detected | Yes - required at all closures per 2022 TGM |
| Screening levels | IDEM Published Levels (via R2 Table 2-A) | BUSTR closure action levels (TGM Table 2.3) |
| Cleanup funding | ELTF (up to $2M per location) | Ohio Petroleum FRAC fund |
The key practical difference: Ohio requires groundwater sampling at every UST closure regardless of whether contamination is suspected. Indiana requires groundwater sampling only when contamination is suspected or detected through visual evidence, field screening, or analytical results. This means a clean Indiana UST removal with no signs of contamination may not require groundwater sampling, potentially reducing closure costs.
Common Mistakes
Not providing 14-day advance notice. This is an enforceable requirement, not a suggestion. Failure to notify or to update IDEM of schedule changes is a violation. Set a calendar reminder.
Submitting composite samples for removal closure. Each UST excavation must be sampled separately with discrete grab samples. Composite samples are explicitly prohibited for removal closures under 329 IAC 9-6-2.6(b)(2).
Missing the 30-day report deadline. The closure report must be submitted within 30 days of completing the physical closure. Have the laboratory on a fast turnaround schedule and start drafting the report before analytical results arrive.
Not sampling under piping runs. Piping and dispenser island sampling is required at 20-foot intervals. This is frequently overlooked, especially on larger sites with long piping runs.
Delaying the release report when contamination is found. If contamination is discovered during closure, report it promptly to the IDEM spill hotline. The 60-day ISC deadline for ELTF coverage starts when the release is reported. Delaying the report delays your client’s ELTF eligibility and triggers coverage reductions.
Not verifying contractor certification. The closure contractor must be certified by the State Fire Marshal. If an uncertified contractor performs the closure, the entire site assessment may need to be repeated.
Key Forms and Resources
UST Systems Closure Report: State Form 56554. Notification for Underground Storage Tanks: Required for any UST registration changes. ELTF Eligibility Application: State Form 55459 (if contamination is found). R2 Table 2-A: Chemicals of concern by product type (in WASTE-0046-R2). IDEM UST Branch contact: (317) 233-5745.
Source
329 IAC 9-6: Closure. 329 IAC 9-6-2.5: Site assessment for permanent closure or change-in-service. 329 IAC 9-6-2.6: Site assessment sampling requirements. 329 IAC 9-4-4: Reporting and cleanup of spills and overfills. IC 13-12-3-2: Remediation and closure goals. IDEM Nonrule Policy Document WASTE-0046-R2: Risk-based Closure Guide. IDEM Storage Tanks website (in.gov/idem/tanks).